1. Field of the Invention
An aspect of the present invention relates to a developing device that can be recycled, and an image forming apparatus using the same.
2. Description of the Related Art
As an image forming apparatus including an optical device for condensing a laser beam onto a scanning surface and performing a straight line scanning, a laser printer has come into wide use. The laser printer exposes a light to a photosensitive body by an optical device, forms a latent image according to letters or image information, and visualizes it as a toner image by a developing device. Then, it transfers the image onto a recording paper by a transfer unit, and fixes it by a fixing unit. As a result, printing is carried out.
In such a laser printer, there is detachably mounted a cartridge type developing device to be exchanged with a new developing device after the toner previously filled in the developing device has been consumed. To the cartridge type developing device, a lid member for closing the filling port to filling a toner is attached. Since the lid member is detachable, even a developing device from which the toner has been consumed can be used as a recycled developing device by detaching the lid member and filling a toner therein again.
The developing device includes a sealing member that prevents a toner from leaking from the developing roller equipped in a developing device or the periphery of the developing roller to the outside. The life of the sealing member is set at, for example, 3 times or less in terms of the filling frequency of a toner. For the recycled developing device, the discrimination from a new developing device or the identification of the filling frequency of a toner is difficult. For this reason, the filling frequency of a toner can not be identified with reliability. Therefore, for every developing device refilled with a toner, the fatigue degree of each component must be checked.
In order to solve the problem, there is proposed a developing device for which the discrimination between the recycled developing device and a new developing device is carried out by displaying and welding the replenishing frequency on a lid material closing a toner filling port (see, e.g., JP-A-4-475).
Also, there is proposed a developing device which has a cylindrical part protruding from the rim of a filling port disposed at the outer wall of a developing case to the outside. In the developing device, the outer edge of the cylindrical part and the lid member are welded. When a toner is refilled therein, the lid member is removed together with the cylindrical part. After refilling a toner, the refilling port is sealed with a refilling port lid member (see, e.g., JP-A-2006-208837)
However, with the technology of JP-A-4-475, the developing case and the lid member are welded. Therefore, the lid member is required to be forcedly detached. Thus, the refilling of a toner is difficult. Further, even when the lid member is detached, the trace of welding remains, which makes it difficult to attach a new lid member.
Also, with the technology of JP-A-2006-208837, the attachment part of the lid member protrudes from the rim of the toner filling port of the developing case to the outside. Therefore, in order to prevent the contact with the protruding part, the image forming apparatus is required to have a clearance part. In other words, the image forming apparatus is required to have a needless space at a position in the vicinity of the toner filling port of the developing device. When a plurality of developing devices are of such a movable type as to repeat contact and withdrawal with respect to a photosensitive body like a color laser printer, the image forming apparatus is further required to have a useless space at a position in the vicinity of the toner filling port of each developing device according to the direction of operation of the developing device.